apache-zookeeper - Apache 馆长 LeaderSelector : How to avoid giving up leadership by not exiting from takeLeadership() method?

Question

I'm trying to implement a simple leader election based system where my main business logic of the application runs on the elected leader node.作为获得领导地位的一部分，主要业务逻辑启动各种其他服务。我正在使用 Apache Curator LeaderSelector 配方来实现领导者选择过程。

在我的系统中，被选为领导者的节点保持领导地位，直到失败迫使另一个领导者被选出。换句话说，一旦我获得了领导权，我就不想放弃它。

根据 Curator LeaderSelection 文档，当 takeLeadership() 方法返回时，领导权将被放弃。我想避免它，我现在只是通过引入等待循环来阻止返回。

我的问题是:

1. 这是实现领导力的正确方式吗？

2. 等待循环(如下面的代码示例所示)是阻塞的正确方式吗？

   public class MainBusinessLogic extends LeaderSelectorListenerAdapter {      
     private static final String ZK_PATH_LEADER_ROOT = "/some-path";
     private final CuratorFramework client;
     private final LeaderSelector leaderSelector;
   
     public MainBusinessLogic() {
       client = CuratorService.getInstance().getCuratorFramework();
       leaderSelector = new LeaderSelector(client, ZK_PATH_LEADER_ROOT, this);
       leaderSelector.autoRequeue();
       leaderSelector.start();
     }
   
     @Override
     public void takeLeadership(CuratorFramework client) throws IOException {
       // Start various other internal services...
       ServiceA serviceA = new ServiceA(...);
       ServiceB serviceB = new ServiceB(...);
       ...
       ...
       serviceA.start();
       serviceB.start();
       ...
       ...
   
       // We are done but need to keep leadership to this instance, else all the business
       // logic and services will start on another node.
       // Is this the right way to prevent relinquishing leadership???
       while (true) {
         synchronized (this) {
           try {
             wait();
           } catch (InterruptedException e) {
             e.printStackTrace();
           }
         }
       }
     }
   }
   

Answer 1

LeaderLatch 而不是 wait()，你可以这样做:

Thread.currentThread().join();

但是，是的，这是正确的。

顺便说一句 - 如果您喜欢不同的方法，您可以将 LeaderLatch 与 LeaderLatchListener 一起使用。